1. Technical Field
The invention relates to the time shifting of television broadcast signals. More particularly, the invention relates to the real time capture, storage, and display of television broadcast signals.
2. Description of the Prior Art
The Video Cassette Recorder (VCR) has changed the lives of television (TV) viewers throughout the world. The VCR has offered viewers the flexibility to time shift TV programs to match their lifestyles.
The viewer stores TV programs onto magnetic tape using the VCR. The VCR gives the viewer the ability to play, rewind, fast forward and pause the stored program material. These functions enable the viewer to pause the program playback whenever he desires, fast forward through unwanted program material or commercials, and to replay favorite scenes. However, a VCR cannot both capture and play back information at the same time.
One approach to solving this problem is to use several VCRs. For example, if two video tape recorders are available, it might be possible to Ping-Pong between the two. In this case, the first recorder is started at the beginning of the program of interest. If the viewer wishes to rewind the broadcast, the second recorder begins recording, while the first recorder is halted, rewound to the appropriate place, and playback initiated. However, at least a third video tape recorder is required if the viewer wishes to fast forward to some point in time after the initial rewind was requested. In this case, the third recorder starts recording the broadcast stream while the second is halted and rewound to the appropriate position. Continuing this exercise, one can quickly see that the equipment becomes unwieldy, unreliable, expensive, and hard to operate, while never supporting all desired functions. In addition, tapes are of finite length, and may potentially end at inconvenient times, drastically lowering the value of the solution.
The use of digital computer systems to solve this problem has been suggested. U.S. Pat. No. 5,371,551 issued to Logan et al., on 6 Dec. 1994, teaches a method for concurrent video recording and playback. It presents a microprocessor controlled broadcast and playback device. Said device compresses and stores video data onto a hard disk. However, this approach is difficult to implement because the processor requirements for keeping up with the high video rates makes the device expensive and problematic. The microprocessor must be extremely fast to keep up with the incoming and outgoing video data.
More recently, digital videos recorders (DVR) have emerged in the marketplace that are based on structures beyond what was previously conceived. One example is U.S. Pat. No. 6,233,389 owned by the Applicant. There are a number of technology trends in force today that are continuing to expand the opportunities for DVR functionality. These trends, whose initial existence directly led to the invention of the DVR, are: the increasing density of gates on semiconductor media; and the increasing density of magnetic storage on hard drive platters.
Two recent announcements bring home these trends with full force.
Until recently, it was believed that the theoretical limit on hard drive platter storage density was 100 Gbits per square inch. This was due to the small number of atoms magnetized at that density versus the effects of parsistic magnetization, which would cause the magnetization to be randomized over short time periods. IBM Corporation recently announced that, by the addition of particlized ferromagnetic material to the platter surface (“pixie dust”), they could achieve 100 times the bit density, or 10 Tbits per square inch. This implies that on a one-inch microdrive (a size that allows placing the drive into a PCMCIA form factor), a density of over 500 GBytes is theoretically possible. This capacity results in over 500 hours of video storage for a typical DVR.
In the semiconductor industry, theoretical limits on chip density have come and gone many times, most of the most recent beliefs was that optical lithography could not etch fine enough lines on silicon. Intel Corporation recently announced that it has developed a transistor ten times smaller than any previously fabricated, from which chips 100 times denser than today's could be developed.